Improper Verification of Cryptographic Signature in hono - CVE-2026-22817
Published: July 24, 2026
Vulnerability identifier: #VU139322
CSH Severity: High
CVSS v4: 8.8 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-22817
CWE-ID: CWE-347
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to forge JWTs and bypass authentication or authorization.
The vulnerability exists due to improper verification of cryptographic signature in the JWK/JWKS JWT verification middleware when processing JWTs with a JWK that does not explicitly specify an algorithm. A remote attacker can supply a crafted token with an attacker-controlled alg header value to forge JWTs and bypass authentication or authorization.
The issue affects configurations that use JWK or JWKS-based JWT verification and rely on the resulting claims for authorization decisions.
Affected software
hono
How to mitigate CVE-2026-22817
Install security update from vendor's website.
hono - update to 4.11.4